8 teraOPS electro-optical DSP

Posted January 20, 2006

Perhaps it's too good to be true, but the technology isn't impossible, merely a little overly specialized. If you want a chip that can churn through 8,000,000,000,000 operations per second, you should have a look at Lenslet.

The way this works is to convert a computational problem into a physical problem: a vector-matrix multiply turns into a vector of lasers, a matrix of light modulators, and a vector of photodetectors. Each laser illuminates a row of the matrix, and each photosensor reads off the sum of the modulated light from an entire column. All the actual multiplication and addition is performed by the photons as they are absorbed by the modulator and shine additively on the detector.

Of course, the catch is (a) you don't have a universal computer at that speed which you can program, merely a DSP that can accelerate certain types of mathematical operations, and moreover ones of particular size ranges, and (b) the answers you get are not guaranteed to be correct, since they are readouts of physical quantities subject to instrumental noise, rather than digital computations with error-correction at every transistor.

Still, for some classes of problems, this is perfect: a lot of the time, you're willing to accept an imperfect answer now as opposed to a perfect answer once the missile you're tracking has already flown past.